Spain

Concerns about the so-called “middle-income trap” have recently emerged among many middle-income countries, particularly after the term was coined in 2007 by two World Bank economists. Worried that they may become “trapped” at the middle-income level, these countries are seeking a set of policies that can help them achieve strong and sustained growth and eventually help them join the league of high-income countries.

In our recent paper, we try to shed some light on both issues. First, we do not find that countries are trapped at middle income. “Escapees” – countries that escaped the middle-income trap and obtained a per capita income higher than 50% of the U.S. level – tend to grow fast and consistently to high income, and do not stagnate at any point as a middle-income trap theory would suggest. In contrast, “non-escapees” tend to have low growth at all levels of income. In other words, while the existence of a middle income trap implies that growth rates systematically slow down as countries reach middle-income status, no such systematic slowdown is apparent in the data. Second, we provide some descriptive and econometric evidence for a different set of “fundamentals” that enable middle-income countries to grow faster than their peers. We find that faster transformation to industry, low inflation, stronger exports, and reduced inequality are associated with stronger growth.

A puzzle: Sanitation is one of the most productive investments a government can make. There is now rigorous empirical evidence that improved sanitation systems reduce the incidence of diarrhea among children. Diarrhea, in turn, harms children’s nutritional status (by affecting their ability to retain nutrients). And inadequate nutrition (stunting, etc.) affects children’s cognitive skills, lifetime health and earnings. In short, the benefits of sanitation investment are huge. Cost-benefit analyses show rates of return of 17-55 percent, or benefit/cost ratios between 2 and 8.

But if the benefits are so high (relative to costs), why aren’t we seeing massive investments in sanitation? Why are there 470 million people in East Asia, 600 million in Africa and a billion people in South Asia lacking access to sanitation? Why are there more cellphones than toilets in Africa?